2011 Nissan Rogue Overheating

[sholston1]

Ok,
Here is the what happens, if you drive 55 to 60 MPH no heating problems. At 65 to 70 and above the temp gauge climbs to the middle and then falls back down to where you can see the entire thermometer emblem on the gauge, then after a short time it will rise again and will not fall back, then it will climb more. If I slow down it will go back down..It seems to get hot quicker if it is hot outside also. We have had the lines pressure tested for leaks, the radiator flushed and filled and the thermostat replaced. Has anyone else experienced this problem. Any help greatly appreciated. Next we are headed for a combustion leak test. Hope someone has some suggestions.
Thanks
Susan

[TrevorK]

To be honest, provided you have enough coolant, you have followed the proper procedure to refill the coolant (to bleed the air out) and you are not losing coolant, it sounds like the problem is related to the engine being overworked or the water pump.

You have eliminated (seemingly) many potential causes: lack of airflow to the radiator, damaged radiator fins, thermostat, clogged radiator, cooling fan. This leaves the major causes as the engine being overlooked and the waterpump/belt. An example of the engine being overworked would be driving in a low gear for long periods of time at higher speeds.

On this site is a factory service manual for your vehicle - if you download it there will be a list inside of what Nissan considers the possible causes. This can help you go through them. The fact that your overheating is tied to the physical speed you are travelling makes me wonder if something is causing the engine to work too hard (dragging brakes?).

[dave08902]

Did you check to see if the front shirt is under the radiator. It is black and behind the bumper underneath. If this is missing or damaged it will disrupt the proper flow of air under the car at high speeds and can cause irregular cooling.

Another thing it could be is a clogged radiator. I had this problem on my old Suburau and I at highway speeds it will overheat as I drove faster. I took out the radiator and had a radiator shop flush it out and it got better but it still ran hot, I eventually changed the radiator and that fixed it. I would suggest that you only use a Nissan radiator because cooling for your CVT is very important and aftermarket radiators will not provide proper cooling and cause transmission issues.

[sholston1]

I checked the skirt thing and the lip that goes across is there and the plastic piece that is like a shield under where the motor is is there but a bolt or screw has fallen out at the back of it, could this be the problem possibly because the air that is going into the grill can escape out the bottom.

[ImStricken06]

have you checked the heater's ability to create heat?

check the hoses on the radiator. get the car running for like 20 mins. tell us the feel of the hoses. the lower and upper. see if the temps change.

also run the car (while parked) without the radiator cap off, and the heater on full blast (hot).